1. Field of the Invention
This invention relates to an improved combustion cylinder construction for an oil space heater, and more particularly to a combustion cylinder construction of the type for radiating heating rays from a double combustion cylinder red-heated by a primary combustion and a white-yellow flame formed at a flame spreading means by a secondary combustion which is capable of improving the radiation efficiency of heat rays and accomplishing the discharge of a clean combustion gas and improvement in combustion performance.
2. Description of the Prior Art
There has been conventionally known a combustion cylinder construction for an oil space heater of the type for emitting heat rays from a double combustion cylinder red-heated by a primary combustion and a white-yellow flame formed by a secondary combustion carried out at a flame spreading means and cleaning a combustion gas due to the secondary combustion. The conventional combustion cylinder construction has disadvantages that it is substantially impossible to uniformly and efficiently red-heat the double combustion cylinder and that an oil burner having the construction incorporated therein is complicated in structure, because the double combustion cylinder and the flame spreading means disposed above the cylinder are respectively surrounded by separate heat-permeable cylinders provided independent from each other in the vertical direction.
In view of such disadvantages, a combustion cylinder construction has been proposed which is constructed in such a manner that a double combustion cylinder and a flame spreading means are surrounded by a single common heat-permeable cylinder. However, such combustion cylinder construction is not adapted to render the supply of a combustion air through a space between an outer cylindrical member of the double combustion cylinder and the heat-permeable cylinder to the flame spreading means uniform with respect to the entire periphery of the flame spreading means, because it is substantially impossible to provide a gap of a uniform distance between the heat-permeable cylinder and a top plate of the outer cylindrical member of the double combustion cylinder. This does not allow a uniform and stable long white-yellow flame to be formed at the flame spreading means as well as the double combustion cylinder to be uniformly and efficiently red-heated.
Furthermore, in such conventional combustion cylinder construction, heat rays are discharged from the combustion cylinder construction through two areas of the single heat-permeable cylinder corresponding to the double combustion cylinder and flame spreading means of the combustion cylinder construction to the exterior of an oil space heater, therefore, heat rays discharged through a section of the heat-permeable cylinder interposed between these two areas are very little in quantity. This causes the heat-permeable cylinder to have nonuniform temperature profiles therethrough, so that an oil space heater having such combustion cylinder construction incorporated therein has a substantially decreased service life.